A method for joining a plurality of metal-made members to be joined by utilizing ultrasonic wave vibration, which has been disclosed in PTL1, is configured so as to join a plurality of metal members while the plurality of metal members which have been stacked up and down are being subjected to a vertical load applied by a joining tool portion of a resonator and an anvil and vibration in a transverse direction due to ultrasonic wave vibration.
However, when a plurality of metal-made members to be joined 101 and 102 which have been stacked up and down are joined to each other by utilizing the joining method disclosed in the above PTL1, the following drawback have been found. When one member to be joined 101 and the other member to be joined 102 of the plurality of metal-made members to be joined 101 and 102 are joined to each other while they are being subjected to a vertical load shown by arrow 106 applied by a joining tool portion 104 of a resonator 103 and an anvil 105 and vibration in a transverse direction shown by arrow 107 due to ultrasonic wave vibration, the plurality of metal-made members cannot be joined in an ingot-like state, in a diffusion-like state, or in an alloy-like state.